Re: [hylafax-users] T.30 T2 timeout, expected signal not received

[Lee Howard <lee.howard@xxxxxxxxxxxx>]

Marcin Giedz wrote:
> I'm facing some problems with sending facsimiles from Hylafax+ version 
> 5.2.7 using IAX modems + Sangom CARD + Asterisk. Connection is 
> established but during "send phase" something goes wrong. Here is the 
> log from last session:
>
> lis 26 13:41:32.34: [ 4853]: SESSION BEGIN 000017120 XXXX
> lis 26 13:41:32.34: [ 4853]: HylaFAX (tm) Version 4.4.4
>
> lis 26 13:41:56.11: [ 4853]: RECV received frame number 33
> lis 26 13:41:56.11: [ 4853]: RECV assumed RCP frame with block end
> lis 26 13:41:56.11: [ 4853]: --> HDLC<5:FF C0 61 96 D3>
> lis 26 13:41:56.11: [ 4853]: MODEM input buffering disabled
> lis 26 13:41:56.11: [ 4853]: --> [10:NO CARRIER]
> lis 26 13:41:56.11: [ 4853]: <-- [9:AT+FRH=3\r]
> lis 26 13:41:56.42: [ 4853]: --> [7:CONNECT]
> lis 26 13:42:02.72: [ 4853]: --> [2:10 03]
> lis 26 13:42:02.72: [ 4853]: --> [10:NO CARRIER]
> lis 26 13:42:02.72: [ 4853]: MODEM No carrier
> lis 26 13:42:02.72: [ 4853]: <-- [9:AT+FRH=3\r]
> lis 26 13:42:02.91: [ 4853]: --> [7:CONNECT]
> lis 26 13:42:12.91: [ 4853]: MODEM TIMEOUT: receiving HDLC frame data
> lis 26 13:42:12.91: [ 4853]: <-- data [1]
> lis 26 13:42:12.92: [ 4853]: --> [2:]
> lis 26 13:42:12.92: [ 4853]: --> [2:OK] 

Just to be clear - on the receive-side you're using HylaFAX 4.4.4 and a 
hardware modem on ttyS7.

What happens is that the received audio is broken in the middle of Phase 
C.  Thus the "assumed RCP frame with block end".  This will happen, for 
example, with jitter.  The receiving modem then goes to listen for the 
partial-page message (+FRH=3 - V.21 HDLC), the receiving modem 
erroneously reports CONNECT (twice) on V.17 audio, and then the 
receive-side gives up.

So there was a glitch in the audio and then a small modem bug on the 
receiver mixed with a less-tolerant HylaFAX operation on the receiver 
caused the failure.

Start analyzing the audio path to figure out why it's being disturbed.  
Even if the receiver didn't have a problem in recovering from this you'd 
still want the audio problem to be fixed.

Thanks,

Lee.

--
*Lee Howard*
*Mainpine, Inc. Software Development Lead*
Tel: +1 866 363 6680 ext 805 | Fax: +1 360 462 8160
lee.howard@xxxxxxxxxxxx | www.mainpine.com


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